Apparatus for making and treating rod-shaped articles

ABSTRACT

The apparatus of the present invention is utilized to treat a wrapped rod-like filler, particularly that consisting of a tow of filamentary filter material which is impregnated with droplets of triacetin of another softening agent that sets more rapidly and/or more reliably in response to heating. The wrapped filler is severed to yield a series of discrete sections, such as filter mouthpieces for use in filter cigarettes. In accordance with the invention, the wrapped filler is or successive sections of the wrapped filler are heated upstream or downstream of the severing station, preferably in a casing containing an elongated guide for the running wrapped filler or for successive discrete sections of the wrapped filler.

CROSS-REFERENCE TO RELATED CASES

[0001] This application claims the priority of the corresponding German patent application Serial No. 101 57 760.5 filed Nov. 27, 2001. The disclosure of the aforesaid German patent application, as well as that of each US and/or foreign patent and/or patent application identified in the specification of the present application, is incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] The invention relates to improvements in apparatus for making and treating rod-shaped articles, such as elongated rods wherein a tubular envelope surrounds a rod-like filler. The apparatus is particularly suitable for the making and treating of rod-shaped articles wherein the filler contains a material (such as a fibrous material) which can intercept tar, nicotine and/or other deleterious ingredients of tobacco smoke.

[0003] It is known to advance a continuous tow of cellulose acetate or the like from a bale through at least one banding device which cooperates with a stretching unit and directs against the tow at least one fine spray of air to convert the tow into a layer of at least substantially parallel filaments. The layer is advanced lengthwise through an applicator serving to spray onto the filaments a mist of finely dispersed softening agent (such as triacetin) which softens minute portions of the filaments prior to advancement of successive increments through a so-called gathering horn wherein the layer of filaments is converted into a rod-like filler ready to be draped into a running web of cigarette paper, so-called tipping paper or other suitable wrapping material.

[0004] The wrapping mechanism normally comprises a paster which applies a film of adhesive to one side of one marginal portion of the web, and such one marginal portion is bonded to the other marginal portion to form therewith a seam extending longitudinally of the thus obtained tubular wrapper. The resulting filter rod is ready to be subdivided into a series of discrete filter rod sections of unit length or multiple unit length, and such sections are fed into a filter tipping machine wherein they are assembled end-to-end with plain cigarettes, cigars or cigarillos of unit length of multiple unit length to form therewith filter cigarettes or analogous smokers' products. Reference may be had, for example, to U.S. Pat. No. 4,412,505 granted Nov. 1, 1983 to Häusler et al. for “APPARATUS FOR APPLYING ATOMIZED LIQUID TO A RUNNING LAYER OF FILAMENTARY MATERIAL OR THE LIKE”.

[0005] In order to promote the setting of the softening agent, successive increments of the rod-like filler are caused to advance through a heating unit which reduces the concentration of the softening agent by causing the softening agent to diffuse into the interior of the filaments, i.e., to become distributed in a much higher percentage of fibers which form the layer and thereafter the rod-like filler. In most instances, the speed of diffusion of the softening agent depends upon the temperature at the heating station, i.e., the rate of diffusion is accelerated if the temperature at the heating station is raised.

[0006] The aforementioned wrapping mechanism normally further comprises an endless belt (known as garniture) which cooperates with stationary draping means to fold the web around the advancing rod-like filler of filamentary material. The garniture serves as a means for advancing the filler through the wrapping station. Reference may be had to U.S. Pat. No. 4,357,188 granted Nov. 2, 1982 to Machida et al. for “METHOD FOR MANUFACTURING CIGARETTE FILTERS”. This patent proposes to advance the rod-like filler through resonance chambers wherein the filler is being acted upon by microwaves. The garniture is in direct contact with the rod-like filler during transport of the filler through the resonance chambers. A similar arrangement is disclosed in German patent No. 29 36 490 C2.

[0007] In order to avoid undesirable repeated heating and potential overheating of the garniture during travel through the microwave applicator which is disclosed in the U.S. Pat. No. 4,357,188 to Machida et al., it is necessary to cool that portion of the garniture which is out of contact with the running rod-like filler. Such cooling is disclosed in German patent No. 2 443 056 B2. The cooling step contributes significantly to the bulk, complexity, initial cost and maintenance cost of the patented apparatus.

OBJECTS OF THE INVENTION

[0008] An object of the present invention is to provide an apparatus which can turn out a rod-like product having a rod-like filler surrounded by a tubular envelope in such a way that at least the major part of the equipment which is used to advance and otherwise treat the filler and/or the finished product need not be heated at all and wherein the heating treatment takes place in a manner and at a location which is less likely to contribute to the cost of the apparatus and/or to shorten the useful life of its parts than in conventional apparatus.

[0009] Another object of the instant invention is to provide an apparatus for making filter mouthpieces for smokers' products which can employ a simple and long-lasting wrapping mechanism for a running rod-like filler of filamentary material.

[0010] A further object of the invention is to provide a novel and improved combination of tow advancing means, tow wrapping means, tow severing means and tow heating means in a machine for making filter mouthpieces for smokers' products.

[0011] An additional object of the invention is to provide a novel and improved heating unit for filter mouthpieces.

[0012] Still another object of the invention is to provide a heating unit which can be put to use in existing types of filter mouthpiece making machines.

[0013] A further object of the invention is to provide novel and improved means for guiding a continuous filter rod or discrete filter mouthpieces through a heating unit for the material of the rod-like filler.

SUMMARY OF THE INVENTION

[0014] The invention is embodied in an apparatus for treating elongated rods wherein a tubular envelope surrounds a rod-like filler. The improved apparatus comprises means for advancing the filler lengthwise in a predetermined direction along a predetermined path (e.g., along an at least substantially horizontal path), means for draping the filler into a flexible web in a first portion of the path to convert the thus draped web into the tubular envelope of the thus obtained rod, and means for heating the filler in a second portion of the path downstream of the first portion (as seen in the predetermined direction).

[0015] The filler can contain a material of the tobacco processing industry (e.g., acetate fibers).

[0016] The apparatus further comprises means for subdividing the rod into a series of rod-shaped sections in a third portion of the path downstream of the first portion; the second portion of the path can be located upstream of the third portion or vice versa.

[0017] The advancing means can comprise means for moving successive rod-shaped sections sideways transversely of the predetermined direction; such moving means can be disposed downstream of the second portion of the path.

[0018] The moving means can be confined in a housing which preferably includes means for thermally insulating its interior from the surrounding atmosphere. The insulating means can comprise an insulating material and/or an air conditioning system.

[0019] The heating means can include guide means which confines the rod (or successive discrete sections of the rod) to lengthwise movement in the second portion of the path; such guide means is or can be stationary, and the advancing means can include means (such as an endless belt) for moving the rod or the sections of the rod relative to the guide means. The latter can include a track for the rod or for successive sections of the rod. Such track can include upper and lower sections which are disposed at least close to the rod or rod sections advancing along the second portion of the path.

[0020] The lower section of the track can provide a substantially concave surface for the rod or rod sections advancing along the second portion of the path.

[0021] In accordance with a presently preferred embodiment of the invention, the lower section of the track includes a plurality of spaced-apart rod-contacting components at least one of which is in at least substantially linear or in at least substantial point contact with the rod or rod sections in the second portion of the path.

[0022] The upper section of the track can be designed to come into mere point contact or linear contact with the rod or rod sections in the second portion of the path.

[0023] The guide means is preferably elongated in the predetermined direction and each of the aforementioned components of the guide means or track can constitute an elongated guide member, e.g., an elongated bar which extends in the predetermined direction.

[0024] The upper and lower sections of the track are disposed at least close to or one of them actually contacts the rod or rod sections in the second portion of the path. For example, the upper section of the track can include one elongated bar having an at least substantially circular cross-sectional outline and extending in the predetermined direction. The lower section of the track can include at least two elongated rod-supporting bars which are spaced apart from each other a distance less than the diameter of the rod.

[0025] At least a portion of the guide means can consist of a heat-resistant material, e.g., of a ceramic material. Furthermore, at least a portion of the guide means can consist of low-friction material.

[0026] The heating means can further comprise a casing which confines the guide means. A portion of the casing, such as a cover, is preferably movable between an open position in which the guide means is at least partly exposed and a closed position. The arrangement can be such that the cover is pivotable between open and closed positions about an axis which is at least substantially parallel to the second portion of the path. At least one section of the aforementioned guide means or track is preferably accessible in the open position of the mobile portion of the casing.

[0027] The improved apparatus can further comprise a safety device (such as a switch) which is arranged to change the condition of the heating means from operative to inoperative in response to movement of the cover of the casing from closed to open position.

[0028] The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved apparatus itself, however, both as to its construction and its mode of operation, together with numerous additional important and advantageous features and attributes thereof, will be best understood upon perusal of the following detailed description of certain presently preferred specific embodiments with reference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING

[0029]FIG. 1 is a schematic elevational view of a machine for making filter mouthpieces which embodies an apparatus constructed, assembled and operatable in accordance with one embodiment of the present invention;

[0030]FIG. 2 is an enlarged view of the heating means in the apparatus of FIG. 1, with a portion of the casing broken away;

[0031]FIG. 3a is a transverse sectional view of the casing, with a cover of the casing shown in closed position; and

[0032]FIG. 3b is a similar transverse sectional view but with the cover shown in the open position.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0033]FIG. 1 shows a filter rod making machine 2 which receives a continuous tow 10 of cellulose acetate fibers from a machine wherein the tow is processed in a manner as disclosed, for example, in German patent No. 42 09 606 A1 or in commonly owned U.S. Pat. No. 5,590,449 granted Jan. 7, 1997 to Chehab et al. for “APPARATUS FOR STRETCHING, PLASTICIZING AND GATHERING A TOW OF FILTER MATERIAL FOR TOBACCO SMOKE”. Thus, a tow of cellulose acetate fibers or other suitable filamentary material is drawn from a bale and is subjected to the action of at least one so-called banding device prior to or simultaneously with stretching of the filaments so as to convert the tow into a layer of at least substantially parallel filaments. The layer is caused to advance through a station wherein its filaments are contacted by a spray of atomized liquid softening agent, such as triacetin. The next stage of treatment involves conversion of the layer into a rod-shaped filler, e.g., not later than during advancement through a so-called gathering horn 17 at the inlet of the machine 2.

[0034] The machine 2 comprises a filler advancing means including an endless conveyor belt 22 known as garniture and serving to indirectly advance the tow 10 lengthwise along an elongated path which is but need not be exactly horizontal and in a first portion of which the tow is draped into a continuous web or strip 21 of wrapping material issuing from a bobbin 18 or an analogous source and advancing along a paster 19. The latter coats one side of one longitudinal marginal portion of the running web 21 with a suitable adhesive (e.g., a hotmelt) which causes the one marginal portion of the web to adhere to the other marginal portion and to form therewith a seam extending lengthwise of the thus obtained tubular envelope which surrounds the filler 10 and forms therewith a continuous filter rod 24. The wrapping unit or wrapping means 23 of the machine 2 comprises stationary components which cooperate with the elongated upper reach of the garniture 22 to convert the web 21 into a tubular envelope surrounding the filler 10. The web 21 can consist of cigarette paper-or any other of several so-called tipping papers including artificial cork, lightweight cardboard or the like.

[0035] The drive means for moving the garniture 22 of the advancing means serves to cause the upper reach of the garniture 22 to advance in a predetermined direction (namely in a direction to the left, as viewed in FIG. 1). Such drive means comprises a suitable prime mover 39 (e.g., a variable-speed electric motor) which is started, arrested, accelerated or decelerated by a control unit 38 of any suitable design. Successive increments of the filter rod 24 issuing from the wrapping mechanism 23 are subjected to the action of a cooling or drying unit 26 which causes the adhesive film between the two overlapping marginal portions of the seam of the converted web to set so that the seam can readily withstand stresses during passage of the rod 24 through a severing device 27 such as a so-called cutoff which is designed to sever the rod 24 at regular intervals so that the rod yields a succession of discrete filter mouthpieces of unit length or multiple unit length. The mouthpieces can be fed into a storage facility or directly into the magazine of a filter tipping machine, not shown.

[0036] A tipping machine which can receive filter mouthpieces from the machine 2 is disclosed, for example, in commonly owned U.S. Pat. No. 5,135,008 granted Aug. 4, 1992 to Oesterling et al. for “METHOD OF AND APPARATUS FOR MAKING FILTER CIGARETTES”. The patented machine is designed to assemble filter mouthpieces of double unit length with pairs of coaxial plain cigarettes of unit length into filter cigarettes of double unit length. Each filter cigarette of double unit length is severed midway across its filter mouthpiece to yield two filter cigarettes of unit length. The means for connecting the plain cigarettes of unit length to the ends of the filter mouthpiece of double unit length includes so-called uniting bands which are pieces of tipping paper each convoluted around the entire mouthpiece of double unit length as well as around the adjacent end portions of the two plain cigarettes.

[0037] Successive filter mouthpieces of double unit length advance lengthwise from the cutoff 27 through a novel and improved heating unit or heating means 28 wherein the minute droplets of the softening agent are stabilized to convert the filler 10 into a filler defining a maze of minute pathways for the flow of tobacco smoke from the lighted end of the finished filter cigarette into the mouth of the smoker. This contributes to interception of tar, nicotine and other undesirable constituents of tobacco smoke. Each of the series of successive filter mouthpieces of unit length or multiple unit length leaving the cutoff 27 and having been treated in the heating unit 28 is accelerated by a rotary cam 29 or another suitable accelerator of the advancing means to be propelled lengthwise into one of axially parallel peripheral recesses or flutes of a rotary drum-shaped conveyor 31 which constitutes a moving means of the advancing means in the improved apparatus. The filter mouthpieces come to rest on the upper reach of an endless belt conveyor 32 which advances them sideways into a strage facility, e.g., a magazine of the filter cigarette making machine such as that disclosed in the aforementioned U.S. Pat. No. 5,135,008 to Oesterling et al. Alternatively, the storage facility can serve as a source of filter mouthpieces for one, two or more discrete filter cigarette making machines.

[0038] The heating unit (microwave applicator) 28 of the machine 2 shown in FIG. 1 includes or is associated with a microwave generator 34 installed in an auxiliary unit 36 of the machine 2. The microwave generator 34 receives signals from the aforementioned control unit 38 which also controls the motor of the drive 39 for the garniture 22. The control unit 38 receives and processes several signals, such as those denoting the speed of operation of the filter rod making machine 2 and preferably one or more additional signals, and regulates the operation of the microwave generator 34 (as well as the drive 39) as a function of the intensities and/or other characteristics of such signals.

[0039]FIG. 1 further shows a temperature sensor 42 which is installed in a housing 40 of the filter rod making machine 2 and transmits signals to the respective input of the microwave generator 34 and/or the control unit 38. The illustrated housing 40 further accommodates the accelerator 29, the conveyor 31 and at least a portion of the conveyor 32. The reference character 40 a dentes a means for thermally insulating the moving means (conveyor) 31, the accelerator 29 and the conveyor 32 (or a part of this conveyor in the interior of the housing 40) from the surrounding atmosphere. Such insulating means can include one or more layers of heat insulating material and/or a suitable air conditioning system (not specifically shown).

[0040] The purpose of the heat insulating means 40 a or an equivalent thereof (or of heat insulating means including the illustrated structure and others) is to prevent too rapid cooling of discrete filter mouthpieces which are treated in the heating unit 28. The aforementioned air conditioning unit for the housing 40 can comprise means for admitting into the housing one or more streams of hot air or another gaseous fluid. The conditioning unit is adjustable, such as in response to signals from the temperature sensor 42, to ensure that the control unit 38 can cause the device 34 to generate microwaves at an optimum rate as well as to change such rate when it departs from an optimum rate and/or to change the rate to a different value (if and when desirable or necessary). All that counts is to ensure that the filter mouthpieces advancing through the heating unit 28 are heated to a selected (optimum) temperature.

[0041] The housing 40 in the machine of FIG. 1 can be said to constitute a facility for temporary storage of filter mouthpieces in a region downstream of the auxiliary unit 36. It is equally possible to make or to consider this housing a part of the auxiliary unit 36.

[0042]FIG. 2 illustrates one presently preferred embodiment of the heating unit 28. This embodiment comprises an elongated block-shaped housing or casing 50 including a main section or portion and a second portion or cover 50 a movable between a closed position (FIG. 3a) and an open position (FIG. 3b). The cover 50 a is secured to the main portion of the casing 50 by one or more hinges 53 each having a pintle 53 a defining a pivot axis which is preferably parallel to the longitudinal direction of the elongated path for lengthwise advancement of the rod 24 and filter mouthpieces toward the accelerator 29 in the housing 40. The lower portion of the casing 50 can be fixedly mounted on the auxiliary unit 36 and/or on or in the main frame of the filter rod making machine 2.

[0043] When the cover 50 a is pivoted to or beyond the open position of FIG. 3b, it exposes and affords access to a novel and improved elongated guide 60 which forms part of the advancing means in the improved apparatus and is installed in the casing 50 between a tubular inlet 56 and a tubular outlet 57 at the respective longitudinal ends of the main portion of the casing 50. A locking device 52 is provided to releasably hold the cover 50 a in the closed position of FIG. 3a. The length of the cover 50 a (as seen in the direction of movement of the filter mouthpieces from the inlet 56 toward the outet 57) preferably approximates (i.e., is only slightly less than) the length of the main portion of the casing 50.

[0044]FIG. 2 further shows a safety switch 54 which serves to change the condition of the heating unit 28 (i.e., of the microwave generator 34) from operative to inoperative as soon as the cover 50 a is pivoted away from the closed position of FIG. 3a, e.g., to that open position which is shown in FIG. 3b or to any open position. The connection (e.g., a cable) from the safety switch 54 to the microwave generator 34 (and/or to the control unit 38) is shown at 54 a.

[0045] The inlet 56 of the casing 50 admits successive discrete filter mouthpieces (arriving from the cutoff 27) into the range of the heating device in the heating unit 28, and the outlet 57 admits heated filter mouthpieces into the range of the accelerator 29 which propels them into the flutes of the conveyor 31.

[0046] The elongated stationary guide 60 is installed in the casing 50 and confines the filter rod 24 (and more specifically the filter mouthpieces which are obtained as a result of repeated severing of the rod by the cutoff 27) to lengthwise movement in the path portion accommodating the heating unit 28. The means for moving the filter mouthpieces lengthwise through the guide 60 can include the endless belt-like garniture 22 and/or one or more other components of the rod advancing means. The illustrated guide 60 can be said to constitute a track along which successive filter mouthpieces advance lengthwise from the inlet 56 toward and into the outlet 57 of the casing 50.

[0047] The guide or track 60 comprises a lower section including two elongated guide members or bars 61, 62 borne by the main portion of the casing 50, and an upper section including a third elongated guide member or bar 63 installed in and movable with the cover 50 a.

[0048] The bars 61, 62 are parallel to and are spaced apart from each other a distance which is less than the diameter of the rod 24 so that successive filter mouthpieces cannot drop into the lower part of the main portion of the casing 50. Each of the bars 61, 62 can be in a more or less linear contact or in mere point contact with a filter mouthpiece advancing through the guide 60. Analogously, the bar 63 can be in mere linear or point contact with a filter mouthpiece advancing through the guide 60 when the cover 50 a is maintained in the closed position of FIG. 3a.

[0049] Each of the bars 61, 62 and 63 can have or has an at least substantially circular cross-sectional outline, and each such bar can consist, at least in part, of a heat-resistant material, e.g., a ceramic material. It is advisable to make such bars of a low-friction material or to impart thereto a finish which entails minimal friction with the tubular envelope(s) of the rod 24 or with the tubular envelopes of discrete filter mouthpieces. The bars 61, 62 and 63 are readily accessible when the cover 50 a is pivoted to open position, e.g., to that position which is shown in FIG. 3b. As can be seen in FIGS. 2 and 3a, the bar 63 of the upper section of the guide or track 60 is parallel to the bars 61, 62 of the lower section of such guide when the cover 50 a is closed. The length of each of the bars 61 to 63 is at least slightly less than the shortest distance between the inlet 56 and the outlet 57 so that the parts 56, 57 cannot interfere with pivotal movements of the cover 50 a and the bar 63 between the positions shown in FIGS. 3a and 3 b. The common axis of the inlet 56 and the outlet 57 is parallel to the longitudinal axes of the bars 61, 62 in each position of the cover 50 a and also to the longitudinal axis of the bar 63 when the cover is closed.

[0050]FIG. 3a shows that the axes of the bars 61, 62 are disposed in a common horizontal plane and that the axis of the bar 63 is disposed in a vertical plane which is located midway between the bars 61, 62. The bars 61, 62 are mounted in two or more supporting walls 64 installed in the main portion of the casing 50 (only one such wall is shown in each of FIGS. 2, 3a and 3 b), and the bar 63 is mounted in two or more supporting walls 66 installed in and pivotable with the cover 50 a.

[0051] The axes of the bars 61, 62, 63 are disposed at the corners of an imaginary equilateral triangle when the cover 50 a assumes the closed position of FIG. 2 or 3 a. The common axis of the inlet 56 and the outlet 57 extends through the center of the triangle. Such arrangement ensures that successive filter mouthpieces advancing beyond the cutoff 27 are compelled to move along an accurately selected path which is or which can be horizontal and ensures adequate exposure of the fillers of successive filter mouthpieces to the heating action of microwaves generated by the component 34 of the heating unit 28.

[0052] An advantage of the casing 50 and of its contents is that the filter mouthpieces advancing from the inlet 56, through the guide 60 and toward and through the outlet 57 are in minimal frictional and heat exchanging contact with solid parts. The bars 61, 62 actually support successive filter mouthpieces which advance through the guide 60, and the bar 63 serves primarily as a means for preventing a filter mouthpiece which advances through the guide 60 from moving out of point contact or linear contact with the bars 61, 62. The clearance between a filter mouthpiece advancing through the guide 60 and any one of the bars 61-63 is preferably minimal. As already mentioned above, the distance between the bars 61, 62 is less than the diameter of the rod 28 (i.e., less than the diameter of a filter mouthpiece), and the same applies for the distance between the bar 63 and the bar 61 and/or 62.

[0053] It is preferred to select the positions of the bars 61, 62, 63 relative to each other in such a way that the longitudinally extending seam of the tubular wrapper of each filter mouthpiece advancing from the inlet 56 to the outlet 57 of the casing 50 is out of contact with the bar 61, 62 and/or 63. For example, the seam can advance through the guide 60 by moving between the bar 63 and the bar 61 or 62.

[0054] The rod advancing means and the means for advancing filter mouthpieces in the apparatus of FIGS. 1 to 3 b are designed and installed in such a way that the kinetic energy of the rod 24 advancing beyond the wrapping mechanism 23 suffices to ensure axial propulsion of the rod 24 into the range of the cutoff 27 as well as the propulsion of successive filter mouthpieces all the way through the casing 50 and into the range of the accelerator 29. Such arrangement ensures highly satisfactory exposure of the fillers of filter mouthpieces to microwaves and warrants the making of the bars 61-63 of a low-friction material. As already mentioned hereinbefore, a presently preferred material for the making of the bars 61-63 is a suitable ceramic material.

[0055] An important advantage of the improved apparatus is that the heating unit 28 is located downstream of the wrapping unit 23, i.e., the heating means is positioned to heat the filler of a finished filter rod 24 either ahead (upstream) or behind (downstream) of the cutoff 27. This is in clear contrast to the teaching of the aforementioned U.S. Pat. No. 4,357,188 to Mochida et al. which proposes to place the microwave application in the region where an endless belt corresponding (by remote analogy) to the garniture 22 in the apparatus of the present invention surrounds the running tow of filter material for tobacco smoke. Furthermore, this is in contrast to the teaching of the commonly owned U.S. Pat. No. 5,590,449 to Chehab et al. wherein the running tow is heated upstream of a unit serving to apply to the filaments a softening agent, such as triacetin.

[0056] The just discussed feature of placing the heating means downstream of the wrapping unit 23 permits for a pronounced simplification of the improved apparatus. This holds especially true if the wrapping unit 23 comprises an endless belt such as the aforementioned garniture. The reason is that the heating unit 28 of the improved apparatus need not heat the garniture 22, i.e., it is not necessary to employ a cooling device to lower the temperature of that portion of the garniture which comes out of contact with the freshly formed rod 24 (between the drying unit 26 for the seam of the tubular envelope of the rod 24 and the cutoff 27).

[0057] The utilization of a heating unit 28 which comprises a microwave generator constitutes an additional novel feature of the improved apparatus.

[0058] It is within the purview of the present invention to place the heating unit 28 upstream or downstream of the cutoff 27, i.e., such heating unit can serve to heat the rod-like filler of the (still) continuous filter rod 24 or successive discrete sections of the rod 24 (namely downstream of the cutoff 27 as actually shown in FIG. 1).

[0059] The preferably drum-shaped conveyor 31 (i.e., that part of the advancing means which serves to positively advance successive sections of the rod 24 downstream of the cutoff 27) is located downstream of the heating unit 28 as seen in the direction of advancement or transport of the rod 24 upstream and of its sections (filter mouthpieces) immediately downstream of the cutoff 27. The placing of the conveyor 31 into the heat-insulated housing 40 greatly reduces the likelihood of too rapid cooling of the filter rod sections, i.e., of a cooling which begins too close to the heating unit 28.

[0060] The guide or track 60 constitutes a presently preferred but not the only available embodiment of the means for ensuring controlled advancement of successive increments of the running rod 24 through the heating unit 28 (the just mentioned increments are constituents of the continuous rod 24 or of successive discrete portions or sections (filter mouthpieces) of the repeatedly severed rod. For example, in accordance with a modification, the illustrated lower portion or section 61+62 of the guide 60 can be replaced with a lower portion or section provided with an at least substantially concave upper side or surface which is contacted by the rod 24 or by its sections (filter mouthpieces). Such modified lower portion or section of the guide can resemble or constitute an elongated channel or trough which is open from above and is in mere linear and/or point contact with the rod 24 or with its sections (filter mouthpieces).

[0061] Each of the bars 61, 62 of the illustrated guide 60 can be designed in such a way that it is in mere two-point or three-point contact (or in a continuous linear contact) with a filter mouthpiece advancing lengthwise through the casing 50. All that counts is to ensure that the area of contact between the guide or track 60 and the filter rod or filter rod sections is as small as possible but is still sufficient to guarantee predictable guidance of the rod 24 or of its discrete sections through the heating unit, i.e., along a portion of the path which is located downstream of the wrapping unit 23 and wherein the filler(s) of the rod or of the rod sections (filter mouthpieces) is or are exposed to heat. Such arrangement entails a minimizing of friction between the tubular envelope (converted web 21) and the mechanical components of the guide and the casing for the guide, i.e., a more predictable guidance for the filter rod and more predictable heating of the filler (converted tow 10) of the filter rod to an optimum temperature.

[0062] Accurate guidance of the filter rod 24 and/or of its discrete sections (filter mouthpieces) brings about the aforementioned additional advantage that the seam of the tubular envelope (converted web 21 of paper, cardboard, artificial cork or the like) can be reliably guided in such a way that it does not or cannot contact (or is less likely to contact) those constituents (such as the bars 61-63) in the heating unit 28 which could or would weaken or otherwise adversely affect the stability, useful life and/or appearance of the seam. For example, excessive contact between the seam and the stationary part(s) in and/or of the casing 50 could entail contamination of the tubular envelope (converted web 21). Moreover, if the contaminant is or includes an adhesive, it could cause neighboring filter mouthpieces to adhere to each other which could affect the operation of a filter tipping machine, i.e., of a machine which normally turns out huge quantities of ultimate products (such as filter cigarettes, cigars or cigarillos) per unit of time.

[0063] The configuration of the upper bar 63 of the illustrated guide or track 60 can match that of the lower bar 61 and/or 62. This contributes to simplicity and hence to lower cost of the guide and even further reduces the likelihood of contamination of the filter mouthpieces.

[0064] The casing 50 and the guide 60 constitute features of the invention which are believed to be novel and patentable in conjunction with other constituents of the heating unit 28, in combination with each other, as well as per se, i.e., irrespective of their utilization in a filter tipping machine, in another machine for the making and/or processing of smokers' products and/or in any other machine wherein an elongated filler is to be confined in a converted web, such as a tubular envelope or the like.

[0065] The feature that the guide 60 is confined in a casing (50) which can be readily opened to afford access to the guide or to a portion of such guide also constitutes an important improvement which is believed to merit patent protection in a machine for the making of smokers' products as well as independently of the purpose and/or nature of the machine in which the casing is being or is intended to be put to use. For example, the casing or an equivalent thereof can afford convenient access to the parts therein as well as to the products which are being caused to pass therethrough, e.g., to permit rapid evacuation of a damaged portion of a continuous filter rod or of one or more discrete filter mouthpieces in the casing or of debris of a partly or fully destroyed portion or section of a filter rod. It has been found that the improved casing contributes to a significant shortening of down times of the improved apparatus and/or of the machine which embodies such apparatus.

[0066] The safety device 54 constitutes an optional but highly desirable and advantageous feature of the improved apparatus. Thus, the operator(s) of the apparatus or of the machine which embodies such apparatus need not be concerned with the possibility of injury to attendants and/or of damage to the machine when it becomes necessary or advisable to gain access to the guide 60, to that portion or to those portions of the rod 24 which happens or happen to be located in the casing and/or to eventually employed or utilized additional component part or parts which is or which are located in the casing or becomes or become accessible only upon opening of the cover 50 a. This is or can be particularly important or desirable if the heating unit 28 operates with microwaves.

[0067] Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic and specific aspects of the above outlined contribution to the art of making and treating filter mouthpieces and other rod-shaped articles and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the appended claims. 

What is claimed is:
 1. Apparatus for treating elongated rods wherein a tubular envelope surrounds a rod-like filler, comprising: means for advancing the filler lengthwise in a predetermined direction along a predetermined path; means for draping the filler into a flexible web in a first portion of said path to convert the thus draped web into said tubular envelope of the thus obtained rod; and means for heating the filler in a second portion of said path downstream of said first portion, as seen in said predetermined direction.
 2. The apparatus of claim 1, wherein the filler contains a material of the tobacco processing industry.
 3. The apparatus of claim 1, further comprising means for subdividing the rod into a series of rod-shaped sections in a third portion of said path downstream of said first portion, one of said second and third portions being located upstream of the other of said second and third portions, as seen in said direction.
 4. The apparatus of claim 3, wherein said advancing means includes means for moving successive rod-shaped sections sideways transversely of said predetermined direction.
 5. The apparatus of claim 4, wherein said moving means is disposed downstream of said second portion of said path, as seen in said predetermined direction.
 6. The apparatus of claim 4, further comprising a housing for said moving means, said housing including means for thermally insulating the interior of said housing from the surrounding atmosphere.
 7. The apparatus of claim 6, wherein said insulating means includes at least one of (a) an insulating material and (b) an air conditioner.
 8. The apparatus of claim 3, wherein said heating means includes guide means for confining the rod to lengthwise movement in said second portion of said path.
 9. The apparatus of claim 8, wherein said guide means is stationary and said advancing means includes means for moving the rod relative to said guide means.
 10. The apparatus of claim 8, wherein said guide means includes a track for the rod.
 11. The apparatus of claim 10, wherein said track includes upper and lower sections disposed at least close to the rod advancing along said second portion of said path.
 12. The apparatus of claim 11, wherein said lower section provides a substantially concave surface for the rod advancing along said second portion of said path.
 13. The apparatus of claim 11, wherein said lower section of the track includes a plurality of spaced-apart rod-contacting components.
 14. The apparatus of claim 13, wherein at least one of said components is in at least substantial point contact with the rod in said second portion of said path.
 15. The apparatus of claim 13, wherein at least one of said components is in at least substantial linear contact with the rod in said second portion of said path.
 16. The apparatus of claim 11, wherein said upper section of said track is in at least substantial point contact with the rod in said second portion of said path.
 17. The apparatus of claim 11, wherein said upper section of said track is in substantially linear contact with the rod in said second portion of said path.
 18. The apparatus of claim 8, wherein said guide means is elongated as seen in said predetermined direction.
 19. The apparatus of claim 8, wherein said guide means comprises a plurality of elongated guide members.
 20. The apparatus of claim 19, wherein said guide members include elongated bars extending in said predetermined direction.
 21. The apparatus of claim 8, wherein said guide means includes a track having upper and lower sections disposed at least close to the rod advancing along said second portion of said path, said upper section including at least one elongated bar extending in said predetermined direction.
 22. The apparatus of claim 8, wherein said guide means includes at least one rod-contacting bar having an at least substantially circular cross-sectional outline.
 23. The apparatus of claim 22, wherein said at least one bar extends in said predetermined direction.
 24. The apparatus of claim 8 for treating an elongated rod having a predetermined diameter, wherein said guide means includes an elongated track having a lower section and an upper section, said lower section including at least two elongated rod-supporting bars spaced apart from each other a distance less than said diameter.
 25. The apparatus of claim 8, wherein at least a portion of said guide means consists of a heat-resistant material.
 26. The apparatus of claim 25, wherein said material is a ceramic material.
 27. The apparatus of claim 8, wherein at least a portion of said guide means consists of a low-friction material.
 28. The apparatus of claim 8, wherein said heating means further comprises a casing confining said guide means, said casing having a portion movable between an open position in which said guide means is exposed and a closed position.
 29. The apparatus of claim 28, wherein said portion of said casing is a cover.
 30. The apparatus of claim 28, wherein said portion of said casing is pivotable between said positions thereof.
 31. The apparatus of claim 30, wherein said portion of said casing is pivotable about an axis which is at least substantially parallel to said second portion of said path.
 32. The apparatus of claim 28, wherein said guide means includes a section which is accessible in the open position of said portion of said casing.
 33. The apparatus of claim 28, wherein said heating means has an operative condition and an inoperative condition, and further comprising a safety device arranged to change the condition of said heating means from operative to inoperative in response to movement of said portion of said casing to said open position thereof. 